TABLE OF THE FAMILIES. 5 



Nciiration not intricate; anterior cross-vein always distinct; laliella of 

 proboscis flcsin- 30 



30. Tlie fourth vein terminates before tlie tip of tlie wing; male sexual 



organs prominent. ....... Apiocekiu.i;. ^oO 



The fourth vein terminates beyond tlie tip of the wing; male se.xual 

 organs small. .... ... Therevii).ic. ^^ 



31. Antenna} with a dorsal arista. ....... 37 



Antennae with a terminal arista or style. ..... 32 



32. Wings pointed, no cross-veins in the middle, the fourtli longitudinal 



vein furcate and arising from the fifth ; small species. 



LONCHOPTEKID.E. 7^3 



Wings rounded at the tip, not lancet-like 33 



33. Second basal cell confluent with the discal cell, not separated b}^ a vein, 



the auxiliary vein does not terminate in the costa; small, mostly 



brilliant-colored, predaceous flies. . . . Dolichopid.'e. 



Second basal cell separated from the discal cell by a vein. . 34 



?A. Antenna with a terminal style 35 



Antennae with a terminal bristle. 3G 



3o. First posterior cell closed (Conopida' pt., Sijrphidii-, jit.) . . 40 



First posterior cell open. ....... Empiive. ^yL 



30. Head comparatively small, the proboscis more or less elongated ; alula 

 of wings usually rudimentary. ..... Empid^e. 



Head as broad as the thorax; proboscis fleshy; alula distinct. 



PlATYPEZID/E. ^"T 



37. Proboscis rudimentary, palpi wanting; first posterior cell usually nar- 



rowed; tcgulffi usually large. Botflies. . . . CEstkid^. 



Proboscis not rudimentary ; palpi present. ..... 38 



38. Second basal cell confluent with the discal cell, not separated by a 



small vein; small, mostly brilliant-colored, prtdaceous flies; face 

 never broad and convex. ..... I)()LiCHOPii>yic. 7fo 



Second basal cell separated from the discal cell Ijy a small cross-vein 

 (if not, not brilliant-colored predaceous flies). . . . 39 



39. Basal cells of wing elongate, the anal cell closed toward the margin ; 



first posterior cell closed or niucli narrowed (excejit sometimes in 

 PipnncAdida). .......... 40 



Posterior basal cell small, the anal cell always closed remote from the 

 margin. ........... 42 



40. Face with subantcnnal vertical grooves or depression. . . 42 

 Face convex transverseh' or witii a meilian ridge; never with a suban- 



temial depression. ......... 41 



